Revision 1298275

FELIX-3377 Applied patch provided by David Jencks (thanks alot) slightly modified:
  - Added some more JavaDoc to ExtComponentContext
  - Have ExtComponentContext extend ComponentContext
  - Internally tread property overwrites like supplied CM configuration
    This allows for properly transient property modification instead
    of overwriting the actual descriptor properties which would cause
    the properties for all instances created from the same descriptor
    to be subsequently modified.